in dichloromethane under Ar atm. Zr complex and Me3SnF in CH2Cl2 were stirred at room temp.for 1 h; soln. was filtered and concd. in vacuo, hexane was added, crystn. at -30°C, Me3SnCl was removed by sublimation (60°C, 3E-1 mbar); elem. anal.;